Penetration depth of electron-doped-infinite-layer Sr0.88_{0.88}La0.12_{0.12}CuO2+x_{2+x} thin films

The in-plane penetration depth of Sr$_{0.88}$La$_{0.12}$CuO$_{2+x}$ thin films at various doping obtained from oxygen reduction has been measured, using AC susceptibility measurements. For the higher doping samples, the superfluid density deviates strongly from the s-wave behavior, suggesting, in analogy with other electron-doped cuprates, a contribution from a nodal hole pocket, or a small gap on the Fermi surface such as an anisotropic s-wave order parameter. The low value of the superfluid densities, likely due to a strong doping-induced disorder, places the superconducting transition of our samples in the phase-fluctuation regime

麦類遺伝資源の探索, アルジェリア, 1989年

The joint mission for collecting wheat and barley varieties in Algeria was carried out during 29 days from May 30 to June 27 1989 with the cooperative works among ITGC of Algeria, ICARDA and Japan (Table 1). Our exploration covered the various areas with mountainous region of Tell atlas, High plateau, Sahara atlas mountains and border region to the desert of Sahara. In all, 257 germplasm samples were collected : 63 Hordeum vulgare, 7 H. distichum, 6 H. bulbosum, 11 H. spp., 46 Triticum durum, 32 T. aestivum, 2 T. spp., 49 Aegilops spp., 1 Avena sativa, 1 Agropyron sp., 2 other Gramineae, 9 Vicia faba, 2 Vicia sativa, 3 Vicia spp., 4 Pisum sativum, 14 Cicer arietinum, 3 Lens culinaris, 1 Phaseolus radiatus and 1 Trigonella foenum-graecum. Also 37 cultivars samples were given from ITGC stock. Most of them are modern varieties and some other samples are collected in Syria. The eastern Telle Atlas mountains, namely Constantine mountains, Medjerda mountains and Djurdjura mountains were partially covered during this exploration and the large diversity of germplasm was observed essentially from standing crops as well as threshing floors and farmer\u27s stores. Aures mountains, which have high altitudes and deep valleys, were also covered and many samples were collected from farmers\u27 store. Because wheat and barley were still green and immature in the fields. In the high elevation of Sahara Atlas mountains, durum wheat was still green but barley was in maturity. In the High plateau, irrigation by pomping up water from a well was frequent and cultivation of durum wheat and barley were observed. The list of collected materials was shown in Table 3 with their passport data and some characteristics. H. bulbosum, which is useful species for haploid breeding techniques, was found growing along the roadside in the montainous and also hilly regions. After checking, its bulb seeds were collected as much as possible in the population. H. distichum was also found in several sites and variation of glume color was recognized. Barley was collected at the mountain gorges in the border of Saharian desert. T. aestivum was frequently found as a offtype in barley or durum wheat field. T. durum, which is a major crop in this country, showed vast variability. Variation about earliness, plant height, glume color, awn color, ear shape and kernel shape were observed in durum wheat. The ear samples of durum wheat from one site showed significant variation on the ear shape and the glume color, and it seemed that the site is a gene pool. Aegilops were frequently observed all the way long of our mission, although two species, namely, Ae. ventricosa and Ae. ovata were dominantly grown, some other unidentified species were also collected. Although Leguminosae was rarely found in the explored region, the cultivation of Vicia faba and Cicer arietinum were observed. Other legumes like Pisum sativum and Lens culinaris were also collected. The assistance of the Director General of ITGC is acknowledged. Thanks are also due to the Algerian authorities and especially to Deputy Director of ITGC, Dr. Feliachi KAMEL, for the permission to collect germplasm and also to its members Mr. Ali ZEGHIDA and Mr. Laddada MOHAMED for the participation. Without their help this mission would not have been possible. Many thanks for Algerian farmers and local persons who gave us their samples and helped us with their traditional hospitality

Optical Properties of Layered Superconductors near the Josephson Plasma Resonance

We study the optical properties of crystals with spatial dispersion and show that the usual Fresnel approach becomes invalid near frequencies where the group velocity of the wave packets inside the crystal vanishes. Near these special frequencies the reflectivity depends on the atomic structure of the crystal provided that disorder and dissipation are very low. This is demonstrated explicitly by a detailed study of layered superconductors with identical or two different alternating junctions in the frequency range near the Josephson plasma resonance. Accounting for both inductive and charge coupling of the intrinsic junctions, we show that multiple modes are excited inside the crystal by the incident light, determine their relative amplitude by the microscopic calculation of the additional boundary conditions and finally obtain the reflectivity. Spatial dispersion also provides a novel method to stop light pulses, which has possible applications for quantum information processing and the artificial creation of event horizons in a solid.Comment: 25 pages, 20 figures, submitted to Phys. Rev.

Impact du barrage de Foum El Gherza sur le développement de l’agriculture en irrigué dans le périmètre de Sidi Okba (Biskra)

Les régions arides à semi-arides en Algérie se caractérisent par la rareté des ressources en eau et par une variabilité accentuée du climat dans l’espace et dans le temps. La retenue du barrage de Foum El Gherza, près de Biskra, pose souvent des questions sur la quantité d’eau disponible et sa variabilité saisonnière, sur la durée de vie de l’aménagement ainsi que sur l’efficacité de l'ouvrage pour l'irrigation. En effet, à partir des années 1990, l’offre du barrage Foum el Gherza sur oued Abiod pour irriguer ce périmètre a fortement diminué sous l’effet conjugué de l'envasement, des sécheresses répétées et d’un accroissement des besoins en eau liés à l’agriculture. L'étude basée sur l'analyse des données d'exploitation du barrage de plus de 50 ans a permis de connaître l’évolution des volumes d'irrigations destinés à développer la phoeniciculture dans la région de Sidi Okba. Confronté aux aléas climatiques et aux fortes traditions sociales ancrées dans le milieu paysan, les oasis de Sidi Okba n’ont pas changé et ont conservé leur aspect traditionnel, probablement à cause de la salinité qui est restée une contrainte majeure jusqu’à nos jours, à l’exception de quelques palmeraies qui ont connu une légère extension. L'étude a montré des dysfonctionnements dans l’exploitation des eaux du barrage pour l’irrigation. On a pu relever le caractère indiscutable de l’augmentation des superficies en particulier durant les deux dernières décennies. La confrontation entre l’évolution du nombre de palmiers avec les volumes d’irrigation, montre les difficultés de mise en valeur et d’extension du périmètre de Sidi Okba ainsi que la gestion des eaux du barrage

Caracterisation des structures n+in+ minces, a base de sillicium amorphe hydrogene par la methode des courants limites par charge d'espace : prise en compte des effets d'interface

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

LES VACCINS anti-SARS-Cov-2 et LES QUESTIONS QU'ILS EVOQUENT

Depuis qu'il a été signalé pour la première fois à la fin de 2019, SARS-Cov-2 a eu un impact mondial sur la santé physique et mentale des humains, ainsi que sur leur vie sociale et leur entreprise économique. En un an, le virus a infecté plus de 115 millions de personnes, en a tué près de 2,6 millions et en a laissé beaucoup d'autres avec des séquelles de santé à long terme. La pandémie de SARS-Cov-2 a submergé les systèmes de santé, a interrompu de nombreux soins de routine et a altéré le suivi des patients. Tous ces facteurs ont conduit à une mortalité accrue due à d'autres maladies chroniques. En outre, la pandémie de SARS-Cov-2 a provoqué une perturbation sans précédent de l'éducation, des activités économiques, des voyages et de la vie sociale et a profondément changé notre mode de vie. Dans cet article de synthèse, nous présentons l'organisation et la fonction du système immunitaire qui nous protège contre les maladies, la virologie, l'infection, la transmission et la pathogenèse du virus SARS-Cov-2, la maladie Covid-19, le développement de vaccins anti-SARS-Cov-2 et certaines des questions soulevées par ces vaccins, ainsi que des suggestions de réponses